Some optical modules may include optical transceivers and generate radio-frequency (RF) Electromagnetic Interference (EMI). For example, a 25.78 Gbps small form-factor pluggable (SFP) optical module may generate RF EMI at 25.78 GHz as an inherent part of its normal operation and radiate the RF EMI from a fiber-attach-latch connector of an optical cable attached to the optical module.
The RF EMI generally escapes the module via various gaps between the module and the fiber-attach-latch-connector. The geometry of the module is defined by the module specification to ensure interoperability between different vendors and, as such, cannot be changed by the module manufacturer to improve the electromagnetic compatibility (EMC).